The invention relates to communication systems, and more particularly to wireless local area network (WLAN) communications systems in which communications characteristics are based on WLAN specifications for the country in which the system is operating.
A WLAN communications system may be implemented by remote terminals (e.g., mobile units) that send messages to and receive messages from base stations or access points using wireless infrared or radio communication links. Each access point or base station covers a limited area, so a typical network may have several base stations or access points.
One protocol that may be used in such communications systems is the IEEE 802.11 Standard as published. The IEEE 802.11 is a standard that defines physical and data link layers for wireless local networks (e.g., networks that include access points and remote terminals). The standard defines, among other things, the wireless local area network (LAN) medium access control (MAC) and physical (PHY) layer specifications.
In the 802.11 standard, for a remote terminal to transmit a message, the remote terminal may first have to become associated with an access point. Association refers to the process of synchronizing a remote terminal with an access point for communication, and is initiated by the remote terminal. The remote terminal may first listen to broadcasts over the airwaves and determine which access points are within range of the remote terminal, and then request association with a particular access point according to certain criteria. At any point in time, a remote terminal is typically associated with only one access point. A single access point can be associated with multiple remote terminals.
With the ever-growing global market, it is common for WLAN users to travel from country to country. A problem therefore occurs, in that one country may allocate a different portion of the frequency spectrum to wireless communications than another country. Different frequency bands or overlapping frequency bands may have been assigned for use by WLAN communication systems of different countries. Typically, WLAN communication systems are assigned to frequencies that do not require the system user to obtain a license from the government to operate the communications system. The unlicensed frequencies for WLAN communications systems of a particular country are typically available for use throughout that country by any WLAN communication system user. Additionally, different countries may have different regulations that provide specifications for operating WLAN systems in that country (e.g., parameters for spread spectrum communications may differ, power requirements may differ, etc.). These allocations and specifications may prevent a remote terminal that is designed for use in one country from working (or being allowed to work or suitably operating) in a WLAN communications system in another country.
What is needed, then, is a system and method for allowing remote terminals to meet regulatory requirements, and adapt to and communicate with access points having different communications characteristics.